Although the etiology of Inflammatory Bowel Disease (IBD) has not been completely defined, significant progress has been made recently in understanding the pathogenesis of these diseases. It is now apparent that IBD develops, at least in part, as a result of a failure to maintain normal host-microbial interactions and mucosal immune homeostasis in a genetically susceptible individual. It is also increasingly clear that many environmental factors can contribute to the development and pathogenesis of IBD, including nutrition, stress, life style and the composition of intestinal microbiota.

Recently, this deeper understanding of the genetic and immunologic factors of IBD has uncovered defects in shared fundamental biological pathways that are associated with cell str